STMicroelectronics LD39200PUR

Overview

LD39200PUR from STMicroelectronics is a 2 A ultra-low-dropout linear regulator with fixed 3.3 V output, input range 1.25–6.0 V, typical dropout of 130 mV at 2 A, ±1 % output accuracy at 25 °C, and 70 dB PSRR at 1 kHz. It features reverse current protection, Power Good flag, thermal shutdown (170 °C), and operates from –40 °C to 125 °C junction temperature - deployed in telecom infrastructure point-of-load (POL) supplies.

For engineers reviewing the LD39200PUR datasheet, LD39200PUR pinout, LD39200PUR application, or LD39200PUR equivalent, key selection criteria include dropout voltage under full load, PSRR performance at switching noise frequencies, Power Good threshold hysteresis (0.92×/0.80×VOUT), reverse current blocking behavior during power sequencing, and DFN6 (3 × 3 mm) thermal resistance (R_THJA = 55 °C/W).

Technical Context

The LD39200PUR uses a PMOS pass transistor architecture enabling ultra-low dropout and inherent reverse current blocking without external components. Its bandgap-referenced error amplifier drives the gate of the PMOS device via an internal op-amp, with RC filtering on the feedback path for stability across ceramic output capacitors (≥10 µF).

Power Good logic monitors VOUT against programmable thresholds (rising edge at 0.92×VOUT, falling edge at 0.80×VOUT) and asserts an open-drain signal; the EN pin provides TTL-compatible control (ON >1.2 V, OFF <0.5 V), reducing quiescent current to 10 nA in shutdown.

Key Specifications

Pinout & Package

LD39200PUR is housed in a thermally enhanced DFN6 (3 × 3 mm) package with exposed pad for GND connection. Pin 1 is OUT, Pin 2 is ADJ/SENSE (tied directly to OUT for fixed 3.3 V operation), Pin 3 is GND, Pin 4 is PG, Pin 5 is EN, and Pin 6 is IN. The exposed pad must be soldered to a GND plane for optimal thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with TPS7A4700RGWR and ADP1740ACPZ-3.3-R7, LD39200PUR uniquely combines sub-150 mV dropout, integrated reverse current blocking, and 70 dB PSRR in a DFN6 package - making it optimal for space-constrained, multi-rail telecom POL where input-to-output voltage margin and power sequencing integrity are critical.

Availability

LD39200PUR is available at Aetrix Electronics and suitable for telecom infrastructure, FPGA power delivery, industrial PLC I/O modules, and 5G small cell baseband applications requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for LD39200PUR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and automotive-grade components with ISO 9001 and IATF 16949 certification.

LD39200PUR belongs to ST's high-performance LDO portfolio targeting telecom and industrial point-of-load regulation, engineered for ultra-low dropout, high PSRR, and robust protection features in thermally demanding environments.

FAQ

What is the minimum input voltage required for LD39200PUR to maintain 3.3 V output at 2 A load?

The minimum input voltage is calculated as VOUT + VDROP = 3.3 V + 0.13 V = 3.43 V under typical conditions. Per Table 5, dropout is 130 mV typ. at 2 A and 25 °C; worst-case (max) dropout is 250 mV across temperature, so VIN ≥ 3.55 V ensures regulation across full operating range. Input below 1.25 V is prohibited per absolute maximum ratings.

Can LD39200PUR be used with only ceramic capacitors, and what are the recommended values?

Yes - LD39200PUR is optimized for ceramic output capacitors. The datasheet specifies ≥10 µF output capacitance with ESR ≤10 mΩ (Figure 20 stability region). Input capacitor should also be ≥10 µF ceramic, placed as close as possible to IN and GND pins. No tantalum or electrolytic capacitors are required or recommended.

How does the Power Good (PG) pin behave during startup and fault conditions?

PG is an open-drain output pulled low (<0.4 V at 6 mA sink) when VOUT falls below 0.80×3.3 V (2.64 V); it transitions to high-impedance when VOUT rises above 0.92×3.3 V (3.036 V). During startup, PG remains low until VOUT crosses 3.036 V, then goes high-Z - providing clean power-OK signaling for FPGA or MCU reset controllers without external debounce circuitry.

Is external compensation required for stability with the recommended 10 µF ceramic output capacitor?

No external compensation is required. The LD39200PUR is internally compensated and stable with 10 µF ceramic output capacitors having ESR between 0.5 mΩ and 10 mΩ, as confirmed by the stability plot in Figure 20 (DS10079 Rev 3, page 12). Adding a 470 nF bypass capacitor further improves high-frequency PSRR but is optional for basic stability.